Heretofore, there has been a rotating electrical machine including core split members which are circumferentially arranged and on each of which a coil is wound in concentrated winding pattern. For such a core, for example core split members made of powder consisting primarily of iron or the like into a nearly-T shape in plan view are used. This core split member generally has a tooth portion extending in a radial direction and a yoke portion wider in a circumferential direction than the tooth portion. The predetermined number of the core split members are circumferentially arranged by making the yoke portions contact with each other to produce a nearly annular core.
Here, there is a shrink fitting method as a method of producing the core by firmly connecting the core split members circumferentially arranged to each other disclosed in for example Patent Document 1 or 2. This method is achieved by circumferentially arranging core split members and fitting a nonmagnetic ring or case heated to high temperatures around the core split members, thereby fastening the core.
Patent Document 1: JP2003-88013A
Patent Document 2: JP2002-136013A